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Wireless Digital Bi-directional Voltage Current Power Meter Ammeter Voltmeter

AprilSteel

Feb 2, 2017
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I have two of these damaged now and seek a circuit or advice on how the circuit might operate.

It has a shunt on the negative line and reads voltage and current from it. Other in and out records are kept and capacity calculated .

The radio part is a transmitter on the shunt component and a receiver separately powered or ,connected by a USB cable if wanted which supplies power also. It uses two nRF24L01 radio modules (they are working ). There is plenty available on these modules.

So I'm looking at the transmitter/shunt and trying to work out how it operates
Anyone got any clues?

Here is a sample with a lot of detail toohttps://www.aliexpress.com/item/DC-...0c89-4e98-895e-a06807106962&priceBeautifyAB=0
 
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kellys_eye

Jun 25, 2010
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The transmitter will use a digital modulation method and the 'code' used will be according to the programming of the controlling processor so unless you can disassemble the program you won't get much information on 'how' the device works.

But the transmitter itself will consume current according to it's mode of operation (details no doubt in the data sheet for the device) so you could monitor it to see if the current is within acceptable levels to prove whether it is actually transmitting or not.
 

AprilSteel

Feb 2, 2017
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No thats not what I mean . I'm not interested in how or why the radio works . I know it does .
Whats happening for instance is,its reading half the voltage it should be ,after I accidentally dropped it on the battery positive and it burnt out a track to earth. One component at least has been damaged and I need a circuit to trace the fault.
 

kellys_eye

Jun 25, 2010
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Those modules tend to use 'standard' interface IC's - like the INA219 for example - so if you can identify the device being used to measure the current you can get the datasheet for it and there may (usually is) find an application schematic that will closely follow the manufactured design. Have a look at the PCB (both sides) to see if you can identify the active component.

Here's the application schematic for the INA219 I mention - note the arrangement of resistors from the shunt, it's worth checking yours see if any are burned....

But this is guesswork as you don't show any pics of the ACTUAL device being used.....

Screenshot from 2018-04-10 22-29-03.png

If the interface is 'entirely' microprocessor based (i.e. one chip with built-in ADC, ROM etc) then you won't get anywhere trying to fix it.
 
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